There have recently been developed and manufactured optical pickup devices for recording or reproducing information on or from optical information recording media such as CDs (Compact Discs), DVDs (Digital Versatile Discs), and BDs (Blu-ray Discs).
For example, as shown in Patent Literature 1, such an optical pickup device includes a light source (for example, a semiconductor laser) and an optical element that transmits light emitted from the light source (for example, an objective lens). The light source includes a heat radiating member that is fixed to components such as a device body and a holder through an adhesive, and radiates heat during emission of laser light. An optical pickup device circuit component such as a driver IC that drives the light source is solder mounted on a circuit patterned on a flexible printed board or a printed board, and solder is also used to electrically connect the optical pickup device circuit component to the light source. Usually, the solder contains, as a catalyst, a flux (containing rosin acid and a hydrogenated rosin acid component as main components) so as to improve soldering property.
Herein, a mixture, that contains aluminum oxide as a main component, and also contains a curable substance having a property capable of curing in air added therein, is used as the material of the heat radiating member for the following reason. This mixture can be easily applied to components such as a holder since it has fluidity before curing, and also can surely radiate heat after curing since aluminum oxide has high heat conductivity. Those capable of generating an alcohol by hydrolysis and condensation reactions to thereby undergo curing are used as the curable substance. The thus generated alcohol is, for example, methanol. When the curable substance is selected so that the generated alcohol contains much more methanol, the time required for curing of the curable substance becomes shorter. In order to cure the curable substance within a comparatively short time, the curable substance may be selected so that only methanol is generated.